Add a second unsafe ES3 API in command buffer.

gpu/command_buffer/client/gles2_interface_stub_impl_autogen.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is auto-generated from
 // gpu/command_buffer/build_gles2_cmd_buffer.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 81 matching lines @@
 void GLES2InterfaceStub::CompressedTexSubImage2D(GLenum /* target */,
                                                  GLint /* level */,
                                                  GLint /* xoffset */,
                                                  GLint /* yoffset */,
                                                  GLsizei /* width */,
                                                  GLsizei /* height */,
                                                  GLenum /* format */,
                                                  GLsizei /* imageSize */,
                                                  const void* /* data */) {
 }
+void GLES2InterfaceStub::CopyBufferSubData(GLenum /* readtarget */,
+                                           GLenum /* writetarget */,
+                                           GLintptr /* readoffset */,
+                                           GLintptr /* writeoffset */,
+                                           GLsizeiptr /* size */) {
+}
 void GLES2InterfaceStub::CopyTexImage2D(GLenum /* target */,
                                         GLint /* level */,
                                         GLenum /* internalformat */,
                                         GLint /* x */,
                                         GLint /* y */,
                                         GLsizei /* width */,
                                         GLsizei /* height */,
                                         GLint /* border */) {
 }
 void GLES2InterfaceStub::CopyTexSubImage2D(GLenum /* target */,
@@ skipping 758 matching lines @@
     GLfloat /* uv_height */) {
 }
 void GLES2InterfaceStub::MatrixLoadfCHROMIUM(GLenum /* matrixMode */,
                                              const GLfloat* /* m */) {
 }
 void GLES2InterfaceStub::MatrixLoadIdentityCHROMIUM(GLenum /* matrixMode */) {
 }
 void GLES2InterfaceStub::BlendBarrierKHR() {
 }
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_INTERFACE_STUB_IMPL_AUTOGEN_H_